A subject of plasmonic spinphotonics is developed for surface plasmon polaritons (SPPs). Since an electromagnetic field is a vectorial field, it has spinning angular momentum, and thus spin current is one of its degrees of freedom. A spin current density tensor has 24 independent components because of its antisymmetry in coordinate indices. By using the law of conservation of electromagnetic angular momentum (i.e., orbital angular momentum plus spinning angular momentum), the electromagnetic spin current density tensor is derived, and its characteristics are indicated. Since surface plasmon polaritons can exhibit various intriguing optical and electromagnetic effects and have many practical applications, we consider a new potential effect relevant to spin current transfer. The electromagnetic spin current density tensor and its intensity profile are analyzed for SPPs sustained on a metal-dielectric interface. The plasmonic spin on a metal ring and a straight thin metal belt is calculated, and based on this, a nanomechanical effect caused by plasmonic spin current transfer is suggested. It is expected that such a nontrivial nanomechanical effect will be useful in the design of new nanophotonic devices aiming at sensitive, accurate measurement techniques.

A compact Ku-band bandpass filter (BPF) with wide pass-band, compact size and high selectively is presented. The presented BPF is composed of two quarter-wavelength resonators and a dual-mode resonator, resulting in a compact circuit size. The transmission zeros (TZs) located at the lower and upper stopband are achieved by the mixed electromagnetic (EM) coupling and dual-mode resonator, respectively, resulting in a high frequency selectively. The measured results show minimum in-band insertion loss, fractional bandwidth and variation of group delay to be 0.9 dB, 36.2% and 0.12 ns, respectively. Also, the stopband suppression is greater than 28 dB from 5 to 10.3 GHz and 30 dB from 19.5 to 29.5 GHz. The effective circuit size of the filter is 8.43×2.28 mm² (0.63 λg ×0.17 λg, where λg is the guide wavelength of 15.1 GHz.)

The configuration of an infinite planar conductive shield is examined when it is excited by an electromagnetic near field generated by a coil current source as that of a wireless power transfer (WPT) system. The analytical expressions of the electromagnetic field based on the transmission theory of shielding are given for different frequencies and different incidence angles of the near field generated by the coil current, assuming the conductive planar shield placed in the close proximity of the coil. The obtained results are discussed and compared with other traditional analytical and numerical solutions.

Based on convoluted interwoven element, a miniaturized frequency selective surface (FSS) with stable band-stop response is proposed in the paper. By extending the four dipoles into the adjacent elements, the equivalent inductance and capacitance are increased, and therefore the proposed FSS realizes promising miniaturization characteristics. The simulation results indicate that the resonant frequency is 1.19GHz, and the dimension is only 0.027λ0. Compared to traditional crossed elements, the size is reduced by 94.6%. Besides, the FSS has excellent angle-stability under both TE and TM waves. Finally, the proposed FSS is fabricated and measured, and the experiment results prove the satisfactory consistency with the simulation results.

This paper presents our research work on designing a dual-band dual-polarized (DBDP) series-fed S/X-band shared aperture antenna (SAA) for synthetic aperture radar (SAR) applications. The proposed SAA DBDP X-band antenna is designed with the concept of series-fed 4-group 2x2 planar arrays with high impedance microstrip line feeding in both vertical and horizontal polarizations. By etching out the inner edge elements from 2x2 X-band subarrays in all the four-groups, the S-band element could be accommodated. The design evolution stages have been presented. The S-band (3.2GHz) is best suited for volumetric soil moisture estimation using SAR and X-band (9.3 GHz) best suited for surveillance SAR applications and grain size estimation. To verify the antenna design concept, a prototype is fabricated and measured with both S-parameters and radiation characteristics including gain measurements. The antenna with reflection coefficient lS11l < -10 dB has an impedance bandwidth 3.12-3.42 GHz (9.3% BW) in S-band and 9.2-9.36 GHz (1.72% BW) in X-band. The measured isolation lS21l between two different bands in the same polarization is better than 25 dB, and the isolation between two different bands in two orthogonal ports is better than 30 dB. Measured gain of the antenna at S-band is better than 8.5 dBi at V-port and H-port, and X-band is better than 11 dBi at either port. Measured side-lobe level (SLL) at S-band is better than -17 dB at either port, and X-band is better than -20 dB at either port. The overall size of the S/X-DBDP SAA is 100 x 100 x 1.6 mm³. Measured results of the S/X-DBDP SAA show good agreement with the finite integration technique (FIT) based computer simulation technology (CST) microwave studio.

The power flow for electromagnetic wave absorbers consisting of pattern conductor layers acting as frequency selective surfaces, absorption layers, and short circuit layers was investigated by Poynting vectors. A method was developed to evaluate the flow of electromagnetic wave power by an electromagnetic wave absorber upon irradiation with electromagnetic waves. The results indicate that the electromagnetic wave absorption phenomenon involves generation of true power, a real part of the time averaged Poynting vector, which moves horizontally along the pattern surface after the incident wave has irradiated the pattern conductor from the vertical direction, and the direction of power flow changes to enter the polymer layer from the pattern interval, causing an accumulation of power inside the polymer layer, followed by absorption, which is converted into heat due to the loss factor.

Phantoms provide valuable test platforms for developing medical devices. Solid materials in particular allow fabrication of stable and robust models. This paper presents a novel, anatomically realistic, multi-layered head phantom made from dielectrically accurate, stable, easily mouldable, low-cost tissue-mimicking materials for testing of microwave diagnostic systems. Also incorporated is a mechanism for inserting reconfigurable lesions and a novel circulatory system modelling physiology. Tissue-mimicking materials composed of graphite, carbon black, and polyurethane with small volumes of acetone or isopropanol were fabricated and dielectric properties were measured across the 1 - 8.5 GHz band. The tissuemimicking material properties were adjusted until their dielectric properties matched those of reference values for target tissues of interest, thereby emulating: weighted aggregates of head tissues external to the brain, tissues comprising the brain, and blood. 3D printed anatomically realistic head and brain moulds cast the phantom mixtures for each layer. Cylindrical holes in the brain layer allow insertion of pathological lesion phantoms, such as haemorrhages. Tubing embedded in the brain layer forms a symmetrical loop providing a novel simplistic model of circulation. The resulting head phantom is anatomically realistic, dielectrically stable, enables pathology modelling, and has, uniquely, a circulatory loop. This novel head phantom provides a valuable test platform for microwave diagnostic studies.

In this paper, off-grid DOA estimation based on sparse representation and Rife algorithm is presented to improve performance when the sparse signal directions are not on the predefined angular grids. The algorithm is divided into two steps. Firstly, the real-valued sparse representation of array covariance vector (RV-SRACV) algorithm is used to do off-grid DOA estimation, and it does not need to estimate the noise power. Secondly, Rife algorithm is used to correct the DOA estimation, and after that the DOA can be accurately estimated. The effectiveness and superior performance of the proposed algorithm are demonstrated in the simulation results.

The least square method has been widely applied in many fields. However, while the approach is used for antenna array pattern synthesis, it is not excellent. In this paper, the least square is used to synthesize antenna array pattern and its performance is reviewed. Then contraposing to the shortcoming of the least square method, a new steerable least square(SLS) method is put forward. For an antenna array whose manifold matrix has been determined, the projection matrix equation can be derived from array manifold matrix easily. In order to get premium solution of array element excitation, a novel projection matrix equation with adjustable matrices is adopted. The results of simulations show that the pattern synthesized by the traditional least square method fits the targeted pattern badly and is worse in the key performance indicators of main-lobe width, peak level of side-lobe and null beam level than the targeted pattern; however, the pattern synthesized by the new SLS method fits the targeted pattern well in zero point and local peak distribution and is better in the key performance indicators of main-lobe width, peak level of side-lobe and null beam level than the targeted pattern.

In this paper, a compact multiple-input-multiple-output (MIMO)/diversity antenna with WLAN band notch characteristics, high isolation, and good ECC suitable for portable ultra-wideband (UWB) applications is presented. The proposed antenna has optimized dimensions of 29 mm × 38 mm. The antenna consists of two orthogonal circular monopoles with a 50 Ω microstrip feed line. In addition, to enhance the impedance bandwidth, a fractal slot, created using Minkowski fractal geometry, is introduced into the ground plane, which is located on the other side of the substrate, just below the feed line. Good isolation (≥ 21.5 dB) with a fractional bandwidth up to 220% is achieved between antenna elements by introducing two ground stubs and a rectangular slot in the ground plane. A band-notch characteristic in the WLAN band is obtained by etching an elliptical split-ring resonator (ESRR) in the radiator. Moreover, a diversity performance of the antenna in terms of ECC (<0.01) and capacity loss (<0.3 b/s/Hz) is performed. This paper offers, for the first time, a combined effect of fractal geometry and ESRR geometry in an antenna design. Finally, a comparison of the proposed antenna is performed with the UWB MIMO/diversity antennas existing in the literature. These results show the suitability of the presented antenna for portable UWB systems.

A new low cost method for implementing an Instantaneous Frequency Measurement (IFM) system is presented in this paper. The proposed method is based on dividing the incoming RF signal into four signals and filtering each one by an appropriate band-pass filter. The frequency is then estimated from the power level of the filtered signals. A closed form for the Standard Deviation (STD) and the bias of the frequency estimator is derived. A design example for an IFM system with a working frequency band of 2 to 4 GHz is presented with simulated and measured results. The design is implemented on a commercial FR-4(DE104) substrate using printed circuit board technology. Experiments in a laboratory show a maximum error of about 15 MHz in estimating the frequency value.

The use of transverse circular representation in circular cylinder coordinate system provides an alternative approach to the solution for vector Helmholtz partial differential equations (VH-PDE) of electromagnetics. After separation, VH-PDE for electric (magnetic) field splits into a set of three ordinary differential (Bessel) equations for two opposite transverse circular polarizations (TCP) and the axial component. The approach is suitable for solving the problem of cylindrical waveguides and cavities starting from the transverse fields. The coupling between TCP fields via the axial component affects nonreciprocal propagation in waveguides. The procedure is illustrated on a dielectric waveguide. It may be extended to the media with circular eigen polarizations including those displaying magnetooptical Faraday effect or optical activity.

This paper presents a dynamic modelling of a series of induction motors (IM) squirrel cage with different shapes of rotor deep bars taking into account the skin effect. The approach is divided into two parts. The first part consists in modelling the skin effect in a rectangular rotor deep-bar with three methods (conventional analytical method, nite element method and analysis method of circuit). These are compared (estimate of the relative error), and subsequently, generalized to more complex forms (trapezoidal, inverted, direct trapezoidal and double cage), done by using the two last methods which take into account the geometrical non-linearity of the slots. The second part consists in a dynamic modelling with variable parameters that take into account the skin effect, simulated for a series of motors with the same power (with different geometric shapes of rotor bars), to see their influence on the starting characteristics of these IM, and the results are compared and discussed.

This paper presents dosimetry of a high resonance wireless power transfer (HR-WPT) system when the transmitter and receiver are aligned and misaligned. An HR-WPT system with two resonant coils and two feeding loops, operating at 13.56 MHz is designed. The power transfer efficiency of the system, and the electric and magnetic fields are investigated using the method of moments. The power transfer efficiency in misalignment situations can be increased by matching the HR-WPT system. Dosimetry of the HR-WPT system is conducted at the optimum matching condition for alignment and misalignment, to achieve the best power transfer efficiency. The specific absorption rate (SAR) is computed using a two-step approach. In the first step, the magnetic fields generated by the HR-WPT system in the absence of a whole-body voxel human model are calculated using the method of moments. In the second step, the SAR in the human model is calculated using the impedance method, with the magnetic fields computed in the previous step regarded as the magnetic fields incident to the human body. Five exposure scenarios are set: one alignment condition and four misalignment conditions. The SAR computed for the alignment and misalignment cases in the matching condition are compared to each other. The compliance of the system is also investigated using the international safety guidelines. Finally, the maximum allowable powers to comply with the guideline are investigated for the five cases considered. The results show that the SARs observed in the misalignment case are higher than those in the alignment case. These results suggest that the misalignment situation should be considered in addition to alignment, when conducting dosimetry of the HR-WPT system.

In this paper, a novel monopole printed fork-shaped antenna for ultra-wideband (UWB) applications with triple band-notched characteristics is presented. The proposed antenna, with compact size of 42×24×1.6 mm³, yields an impedance bandwidth of 3.1-11 GHz for S11 < -10dB, except on the notched bands which are obtained by introducing three different types of slots. A U-shaped and two extended U-shaped defected ground structure (DGS) slots give respectively two notched bands， 3.3 to 3.7 GHz for WiMAX and 7.1 to 7.76 GHz for downlink X-band satellite communication systems. Therefore, a semi arc-shaped slot is etched on the radiating patch to notch the band from 5.15 to 5.825 GHz for WLAN applications. The proposed antenna is fabricated and measured.

We present an angular stable dual-band frequency selective surface (FSS) in this paper. By placing anchor-shaped elements with different structural parameters along x-axis alternately within hexagonal wire grid, the proposed FSS can provide two closely spaced passbands. And the resonant frequency ratios are only 1.16 and 1.19 for TE and TM polarizations, respectively. In addition, the proposed FSS has stable frequency response under oblique incidence, and resonant frequency deviation is below 0.5% within 60° incident angle. An FSS prototype is fabricated and measured for further verification, and good agreements between the simulated and measured results can be observed.

We proposed an efficient method to radiate the spoof surface plasmon polaritons (sspps) to the endfire direction, which added two parasitic strips as directors in front of the dipole antenna fed by the sspps structure. The directors were used to enhance the endfire radiation due to its beam modified function. Both simulated and measured results suggest good performance of the proposed antenna in a narrow band from 6.5 to 6.9 GHz with about 7.5 dBi realized gain and a 5 dBi increase in the endfire direction at the center frequency of 6.8GHz reference to the unloaded structure. Also, the surface electric field distributions of the unloaded and loaded sspps antenna were studied to verify the gain enhancement in the endfire direction in physical perspective. Our work tends to have better performance than other related work, such as broader bandwidth and higher realized gain with even greatly simplified design process. The proposed sspps antenna has potential applications in planer integrated circuits and communication systems.

A broadband right-hand circularly polarized (RHCP) cross-type traveling wave antenna array is proposed for High-Rate Close Proximity (HRCP) point-to-point (P2P) wireless communication system at 60 GHz. Instead of low temperature co-fired ceramic (LTCC) technology, a single-layer structure of the proposed 2x1 element antenna array is fabricated with a conventional printed circuit board (PCB) process, to provide low manufacturing cost and low profile (0.05 λ0 at 60 GHz). A wide impedance bandwidth (57-64 GHz, VSWR < 2) and broad RHCP bandwidth (57-64 GHz, axial ratio (AR) < 3 dB) are achieved. The RHCP gain is higher than 6 dBic in the entire operating frequency band (57-64 GHz).

In this paper, the inverse scattering of a conducting cylinder is given by modified fireworks algorithm. Initially, the direct scattering is formulated as an integral equation, which contains the target shape function. The scattering integral equation is then solved by the moment method. To achieve image reconstruction, the target shape function is expanded as a Fourier series. The inverse scattering is transformed into a nonlinear optimization problem. The variables are Fourier series coefficients of the target shape function. The objective function is defined by comparing the scattered electric fields of guessed and true shapes. This nonlinear optimization problem is then optimized by our modified fireworks algorithm. The fireworks algorithm is a novel swarm intelligence algorithm for global optimization. It is inspired by practical fireworks explosion. In this paper, it is suitably modified so that it can treat the inverse scattering problem with fast convergence. Numerical results show that the inverse scattering based on our modified fireworks algorithm can accurately reconstruct the target shape with fast convergence.

In this paper, a new flower-shaped microstrip line feed reconfigurable band-notched UWB monopole antenna using single varactor diode is introduced and fabricated. Different notch frequencies can be obtained using different capacitor values. The effect of changing the varactor position is also examined. The flower shape is first optimized to obtain UWB characteristics. Then, a slot is made in the microstrip line to be loaded later with a single varactor diode. A wide range of notch frequencies can be obtained using this simple configuration which cover most of the narrow band coexistence systems. The notch frequency can be lower by increasing the capacitance value. The notch frequency covers the WLAN band when C=0.8 PF and covers the WIMAX band when the capacitance is changed to 0.7 PF for the same antenna configuration and varactor position. Two prototypes of the proposed antenna using two different single capacitor elements with capacitances 0.6 PF and 1.5 PF are fabricated, and their reflection characteristics are measured and compared with the simulated ones. Notch frequencies at 6.1 GHz and 4.3 GHz are obtained respectively in both simulated and measured antenna structures. The proposed antenna a directive radiation pattern in E-plane and omnidirectional pattern in H-plane. Also the gain is suppressed in the notched frequencies. The group delay is nearly stable in the UWB frequency range with very little variations, but it is distorted sharply at the notch frequencies. So, the proposed antenna is a good candidate for the modern UWB systems.